With the advent of technology, electromagnetic spectrum has enabled transmission of any data or information at a much higher speed and with greater efficiency. Consequently, several vital activities such as broadcast of mass media content via cellular, and satellite networks, infrared communication, Bluetooth communication, microwave radio, ZigBee, Wi-Fi communication and so forth have been facilitated by the electromagnetic spectrum. Moreover, the radio frequency spectrum has increasingly mobilized the use of cellular phones and revolutionized the field of wireless communication.
However, the electromagnetic spectrum is a limited resource. In earlier days, distribution and use of spectrum was relatively easy, owing to a small number of users and fewer uses thereof. However, with an increase in the number of users and uses of the electromagnetic spectrum, a need for effective management of the electromagnetic spectrum has emerged. Typically, mobile networks have high demand for country wide network coverage and data capacity. Mostly, the frequency assignments of mobile, public safety, and military radio networks have their own dedicated frequency bands. The demand of spectrum by the public safety networks and the military networks has increased owing to the increase in digital radio communication. Furthermore, during a crisis situation, such as a natural disaster or a war, public safety networks and the military networks require larger spectrum for their services. Public safety and military have a growing interest to utilize also the mobile frequency bands due to increasing use of video content, which requires larger frequency bands than the voice or small data transfers, and attractiveness to use equipment, which has been developed for mobile use. A scenario, how this could happen is that public safety or military share a frequency band, by allowing the mobile operators to have secondary access on public safety or military bands. The priority order of the possible sharing among mobile, public safety, and military depends, for example, on laws, regulations, and licenses governing a specific frequency band.
The conventional methods for commercial spectrum use are licensed use and license-exempt use. Military and other governmental bodies may have an own way of allocations, which may or may not override the commercial radio licenses, depending on the country. Between licensed and license-exempt use, there might be regulations, where a radio license is required, but protection from interference from other license holders is not guaranteed. The license holders may be required to coordinate the radio spectrum use among themselves or use equipment, which can do it automatically. It is also possible to have an independent radio resource reservation system on such frequency bands. In a majority of cases, a government body allocates spectrum to the plurality of mobile networks through a predefined procedure such as auction.
The capacity mobile bands, which are mainly on the frequencies above 2 GHz, practically no operator deploys a nationwide coverage. That leaves a lot of geographic areas, where secondary use would not cause any harmful interference to the mobile operator. On the other hand, public safety and hybrid-war military use is local or regional, and the duration of the use is also relatively short. From this perspective, the use of radio frequencies could be used more efficiently by sharing them between plurality of networks. In the current sharing agreements, the priority order between the plurality of networks is fixed and exceptions to the priority order require at least negotiations and agreements between the parties, and they may require political decisions, law, and regulatory changes. Such processes take a long time compared to the delay tolerated by the PPRD and military missions.
A recent development in spectrum management is Dynamic Spectrum Access (DSA). Current standards and regulations related to DSA include Television White Space, Licensed Shared Access, and Citizen's Broadband Radio Service. Characteristic to these systems is that the information about the use of primary spectrum use is maintained in the system, and the system is able to make changes to the secondary use to ensure that secondary systems do not cause harmful interference to the primary user. DSA systems are automated, and they can react fast, typically in seconds or minutes, to changes. All standardized and regulated DSA systems, so far, have a fixed priority order between the primary and secondary spectrum users.
The criticality of spectrum use by public safety and military communications vary. If the use is related to training, demonstrations, or similar activities, secondary priority might be enough. Public Protection and Disaster Recovery (PPDR) and mission-critical military operations, require the primary priority.
Typically, each of the plurality of network uses the allotted spectrum for their service. Consequently, the allocated spectrum is not used efficiently and optimally by each of the plurality of networks. Traditionally, existing systems contain time based control of spectrum via the spectrum management platform. However, such systems used for spectrum management practices are static in terms of administration, geography, spectrum allocation and so forth. Furthermore, reallocation of frequency parameters is a tedious and difficult process.
Therefore, in light of the foregoing discussion, there exists a need to overcome the aforementioned drawbacks associated with the conventional spectrum management systems. There is a need to have a spectrum sharing system with changing priority order between the plurality of networks. The system should have a possibility for pre-agreed priority changes between the plurality of networks. The changes should be possible to deploy within the time delay that can be tolerated by PPDR and military actions.